Abstract: A well perforating apparatus includes an underbalancing valve for opening ports in a tubing string immediately subsequent to the firing of a perforating gun, and comprises a hollow conduit having at least one pair of axially aligned, and radial holes traversing the wall of the conduit. A frangible member has its end portions slidably and sealably mounted in such holes and is therefore disposed transversely to the path of a detonating bar which is dropped to initiate the firing of the perforating gun. Upon breakage of the frangible member, the ends of the bar are forced inwardly out of the holes by the fluid pressure differential existing between the interior and exterior of the conduit due to the underbalanced fluid pressure condition achieved in the tubing string prior to firing the perforating gun.

Abstract: The present invention provides a method for removing incipient carious lesions and/or stain from human teeth. The method of the present invention comprises the steps of aiming a yttrium-aluminum-garnet laser so that its output inpinges upon the lesion and/or stain and thereafter repeatedly activating the laser in pulse mode until the incipient carious lesion and/or stain is removed from the tooth.

Abstract: A posterior chamber lens implant is disclosed for use after extracapsular surgery. In extracapsular surgery the interior of the lens of the human eye is evacuated through a surgical opening formed in the front membrane of the lens while leaving the rear membrane of the lens or posterior capsule intact. The lens implant comprises an optic having a front surface and a rear surface and the implant is secured within the posterior chamber of the eye. In one form of the invention, a ridge spaces the rear surface of the optic forwardly from the posterior capsule while in a second form of the invention, the rear surface of the optic is concavely formed to space the rear surface of the optic forwardly of the posterior capsule. The implant of the present invention thus facilitates laser posterior capsulotomy in the event of clouding of the posterior capsule following the extracapsular surgery.

Abstract: A prevailing torque type self-locking nut has an internal aperture provided with wedge ramp type threads, the aperture being tapered in cross section adjacent the top of the nut.

Abstract: A locking thread insert is wound from wire which is drawn to a generally diamond-shaped cross-section. The wound wire is coiled to a predetermined diameter preferably slightly larger than the diameter of a threaded hole in a female member in which the insert is to be disposed. The threaded screw is free-running in the insert until a predetermined magnitude of loading is encountered at which time a locking and anti-vibration interaction occurs between the crest of the male thread on the screw and the insert. The crest of the male thread is radially compressed when moved axially and circumferentially so as to positively resist loosening under vibration. The interaction between the insert and screw also positively seats and locks the insert in the female member.

Abstract: A posterior chamber lens implant is disclosed for use after extracapsular surgery. In extracapsular surgery the interior of the lens of the human eye is evacuated through a surgical opening formed in the front membrane of the lens while leaving the rear membrane of the lens or posterior capsule intact. The lens implant comprises an optic having a front surface and a rear surface and the implant is secured within the posterior chamber of the eye. In one form of the invention, a ridge spaces the rear surface of the optic forwardly from the posterior capsule while in a second form of the invention, the rear surface of the optic is concavely formed to space the rear surface of the optic forwardly of the posterior capsule. The implant of the present invention thus facilitates laser posterior capsulotomy in the event of clouding of the posterior capsule following the extracapsular surgery.